JP2704621B2 - Solid solution - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a solid solution useful as a guest / host type nonlinear optical material.

[Prior Art] In recent years, nonlinear optical responses such as optical second harmonic generation (SHG), optical third harmonic generation (THG), optical phase conjugation, and optical bistable have been known for all solid, liquid and gaseous substances. Have been. Among them, the progress of organic nonlinear optical materials has been remarkable, and there have been found materials having better performance by at least two orders of magnitude than inorganic materials. However, it is technically difficult to obtain a single crystal having a sufficiently large nonlinear optical effect among such nonlinear optical materials, and it is expensive.

On the other hand, attempts have been made to obtain large thin films or fibrous single crystals by vapor deposition or zone melting in a capillary. [Naya B.K., "AS CS Symposia" (Nayar, B.
K .; ACS sym.) 153, 1983].

However, it is difficult to control the single crystal to a phase-matched orientation necessary for efficiently obtaining SHG and THG, which are nonlinear optical effects.

Also, there is known a method in which a guest compound having a large nonlinear optical constant is put in a host molecule and an electric or magnetic field is applied to align the crystal in order to control the crystal structure instead of using a single crystal.

For example, an attempt has been made to arrange polar molecules using a polymer liquid crystal as a host and polar molecules as a guest by using the electric field orientation of the polymer liquid crystal, and SHG has been observed by applying a voltage [Meredes G. R. et al. Macromolecules ”(Meredith, GRet al; Macromolecules,) 15 , 13
85, 1982].

As an example of aligning polar molecules in an amorphous polymer, an azo dye is dissolved in a polymethyl methacrylate resin to form a thin film, and then heated to a temperature equal to or higher than the glass transition point, and a voltage is applied to the azo dye molecule to form a thin film. A non-linear optical constant of 6 × 10 ⁻⁹ esu was observed by cooling the array while fixing the structure. [Singer Kay
Dee, Thorne Jee, Larama SJ "Applied Physics Letters" (Singer, K.
D., Sohn, JEand Lalama, SJ; Appl. Phys. Lett.,) 49 , 24
8, 1986].

As another related art, a polymer nonlinear optical substrate is added by adding a nonlinear optically responsive organic compound to a polymer based substrate described in JP-A-57-45519 and U.S. Pat. No. 4,428,873. It is stated that it can be obtained. Further, as described in JP-A-62-84139, there is a nonlinear optical substrate in which an acrylamide resin is used as a host polymer and a nonlinear optically responsive organic compound is used as a guest. Further, JP-A-62-246962 describes that a compound having an asymmetric center is grown in a polyoxyalkylene oxide matrix.

Further, non-linear optical materials obtained by using a polyoxyalkylene matrix as a host by using an electric field crystallization technique are described in Japanese Patent Application Nos. 62-51786 and 62-54439.

Such a polymer-based nonlinear optical material is excellent in processability such as thinning while retaining an electron interaction that produces a nonlinear optical effect, and is a material suitable for device fabrication.

[Problems to be Solved by the Invention] Generally, as the content of the guest molecule in the solid solution increases, the nonlinear optical effect increases in proportion to the amount,
Large amounts of low molecular polar compounds that are guests to high polymers such as acrylic resin and ordinary homonylon, for example,
It is difficult to uniformly blend at least 20% by weight or more at the molecular level, and a guest molecule may partially undergo phase separation and cause defects such as crystallization.

Further, in such a blend polymer, particularly when the content of the low molecular polar guest increases, the flexibility of the polymer itself tends to be lost, and the mechanical strength tends to be greatly reduced.

Regarding the second-order nonlinear optical effect, even if the polarizability β is large for a single guest molecule, if it is a centrally symmetric crystal, there is no SHG activity even if it is mixed with a conventional polymer, or it is negligible. . Therefore, it is usually necessary to form a film, apply an electric or magnetic field, or stretch and orient the film.

The present invention has been made to solve such problems of the prior art, and an object of the present invention is to easily and uniformly form a guest organic compound having a large non-linear polarizability in a host polymer compound. Compatible and 2 of guest organic compounds
The second-order and third-order nonlinear optical effects are not reduced by blending with the host polymer compound, and have flexibility even when a large amount of a guest organic compound is contained, and have excellent mechanical strength and workability. To provide a new solid solution.

Another object of the present invention is to blend a guest organic compound having a large β in the second-order nonlinear optical effect but having a centrally symmetric crystal with a single guest organic compound and no SHG activity at all with the host polymer compound. By doing
An object of the present invention is to provide a solid solution capable of expressing a large SHG activity.

[Means for Solving the Problems] and [Action] That is, the present invention comprises a host polymer compound comprising a copolymerized nylon and a guest organic compound having both an electron-withdrawing group and an electron-donating group. The content of the guest organic compound is 15 to 90 with respect to 100 parts by weight of the host polymer compound.
It is a solid solution characterized by being part by weight.

 Hereinafter, the present invention will be described in detail.

The host polymer compound used in the present invention is made of copolymerized nylon, and excludes ordinary nylons such as nylon 6 and nylon 66. The copolymerized nylon is obtained by mixing and copolymerizing two or more types of homonylon raw materials (monomers).

Representative examples of monomers include ε-caprolactam, a raw material for nylon 6, 11-aminoundecanoic acid, a raw material for nylon 11, ω-laurolactam, a raw material for nylon 12, and hexamethylenediamine / adipin, a raw material for nylon 66. And hexamethylenediamine / sebacate, a raw material of nylon 610, and hexamethylenediamine / laurate, a raw material of nylon 612.

Examples of copolymerized nylon include ε-caprolactam,
Nylon 6/66/61 consisting of nylon 66 salt and nylon 610 salt
0 terpolymer, ε-caprolactam, nylon 66
6/66 / consisting of salt, ω-laurolactam, and nylon 610 salt
12/610 quaternary copolymer.

The molecular weight of the host polymer compound composed of copolymerized nylon used in the present invention is desirably a weight average molecular weight of 5,000 or more, preferably 10,000 to 300,000, from the viewpoint of mechanical strength.

The host polymer compound in the present invention may be used by blending a homopolymer of copolymerized nylon or a polymer compatible with copolymerized nylon. Examples of the polymer that is a blend include an acrylic resin, a butyral resin, a styrene copolymer, a polyethylene oxide resin, and a polyvinylidene fluoride copolymer.

Also, when blending, the copolymerized nylon is at least 20% by weight or more based on all the blended host polymer compounds,
Preferably, it accounts for 50% by weight or more.

Next, the guest organic compound used in the guest-host type solid solution of the present invention is a compound having a charge asymmetric electronic structure having both an electron-withdrawing group and an electron-donating group in the molecule, and is generally a low-molecular compound having a molecular weight of about 1,000 or less. It is.

Examples of suitable guest organic compounds include the following.

Examples of guest organic compounds (1) (H ₂ N) ₂ CO The guest / host type solid solution in the present invention can be produced by dissolving a host polymer compound and a guest organic compound having both an electron-withdrawing group and an electron-donating group in a common solvent, and then removing the solvent. . Suitable solvents include methanol, ethanol, propanol, triene, benzene, methylene chloride, 1,4 dioxane, and the like.

As a further alternative, the solid solution can be prepared by mixing the guest component and the host component and heating the mixture to a molten phase. When this molten phase is cooled to room temperature, a homogeneous solid solution is obtained. The guest organic compound is at least about 15 per 100 parts by weight of the host polymer compound.
Parts by weight, preferably 15 to 90 parts by weight. Generally, the non-linearity increases as the guest component increases. The solid solution using the copolymerized nylon of the present invention as a host polymer has flexibility and excellent mechanical strength even when the guest component is increased.

On the other hand, even if a solid solution is prepared with a homonylon such as nylon 6 or nylon 66, a solid solution having uniform mechanical strength cannot be obtained. As one of the reasons, it is considered that copolymerized nylon has lower crystallinity than homonylon, so that compatibility with guest organic molecules is increased and flexibility can be maintained.

The solid solution of the present invention is generally a material exhibiting non-linear optical response such as hyperpolarization tensor characteristics, optical phase conjugation, optical bistable like SHG and THG. In particular, when it comes to SHG, p
-The guest organic compound is a centrally symmetric crystal like nitroaniline, and even if it shows no SHG activity by itself, it is large and uniform only by blending it with copolymerized nylon.
It was surprisingly found that SHG activity could be expressed. Conventionally, one of the reasons for this is for guest molecules,
It is considered that the copolymerized nylon exerts a strong interaction between molecules and makes it difficult to maintain the central symmetry of the guest molecule.

For this reason, in order to exhibit the second-order nonlinear effect in the related art, it is an essential condition that the crystal is not a centrosymmetric crystal. However, a compound having a higher polarizability tends to have a higher central symmetry. Therefore, as a method of destroying the central symmetry, a device such as introduction of a substituent into an asymmetric position has been devised. However, in the guest / host solid solution of the present invention, a guest organic compound having a centrally symmetric crystalline structure can be applied. Can be.

According to the present invention, the solid solution can be formed into a thin film and irradiated with a laser beam to obtain a harmonic by SHG or THG by scattering, and display can be performed. In this case, even if a guest organic compound having a symmetric center crystal is used as a guest molecule alone, the solid solution of the present invention does not require orientation by an electric field or a magnetic field, and can obtain a large harmonic of scattered light.

On the other hand, as a thin film waveguide or fiber,
When using G and THG, it is necessary to perform phase matching, and this can be achieved by orienting guest molecules by electric field, magnetic field, stretching or the like. Specifically, the solid solution formed into a film is heated to a temperature higher than the glass transition temperature Tg of the host polymer, more preferably to a temperature close to the crystal dispersion temperature, and then an electric field, a magnetic field or stretching, and a temperature around the Tg or
When cooled to a temperature lower than Tg, the molecular orientation of the guest molecule is structurally fixed.

The molecular orientation in the host / guest solid solution can be confirmed by X-ray diffraction analysis.

[Examples] Next, details of the present invention will be described based on examples.

Example 1 The production of a solid solution according to the present invention is illustrated. 6/66/12/610
To 10 parts by weight of a nylon quaternary copolymer (CM8000, manufactured by Toray Industries, Inc.), 50 parts by weight of ethyl alcohol and 2.5 parts by weight of p-nitroaniline are added, and the mixture is heated to 65 ° C. with stirring to dissolve.

Cast the above homogeneous mixed solution on a glass substrate,
The solvent was removed by heating to obtain a uniform host / guest type solid solution in the form of a film having a thickness of about 300 μm.

This film-like solid solution was mechanically strong and had flexibility, and no special attention was required for handling.

[Measurement of SHG Intensity] Next, SHG intensity was measured in order to examine the nonlinear optical effect of the solid solution obtained in Example 1.

Using a Nd: YAG laser as the light source, it emits light with a wavelength of 1.06 μm (output 3 mJ / pulse, repetition 10 Hz)
The intensity of SHG light (0.53 μm) was observed with a photomultiplier.

The results are shown in Table 1 below, where the guest molecule alone was SH
Although G was not shown, strong SHG was observed in the host / guest type solid solution.

In Table 1, the intensity indicates a relative intensity with urea being 1.

Example 2 2 parts by weight of N, N-dimethyl-p-nitrobenzene as a guest organic compound were mixed with 10 parts by weight of the same copolymerized nylon as in Example 1 in an ethanol solvent, cast, and the solvent was distilled off by heating. Then, a uniform host / guest type solid solution having a thickness of about 100 μm was produced.

Next, a solution obtained by dissolving the solid solution obtained in Example 2 in benzene was spin-coated on a glass substrate obtained by evaporating aluminum and evaporated to dryness while maintaining the temperature at 60 ° C., whereby a uniform film was obtained. Further, aluminum was evaporated to obtain a waveguide type nonlinear optical element. The temperature of the device was raised to 80 ° C., and the device was cooled to room temperature while applying an electric field of 500 V / cm to the upper and lower aluminum electrodes.

This Nd-YAG laser (wavelength 1.064μ)
m) is condensed and irradiated, and the second harmonic of the light (wavelength 0.
532 μm) was observed by a photomultiplier.

Example 3 To 10 parts by weight of the same copolymerized nylon as in Example 1, 2 parts by weight of 4-aminobenzonitrile as a guest organic compound was dissolved by heating in 100 parts by weight of an ethanol solvent. The solution was cast and the solvent was distilled off by heating.
A uniform host / guest type solid solution of 0 μm was produced.

Next, a solution obtained by dissolving the solid solution obtained in Example 3 in benzene was spin-coated on a glass substrate obtained by evaporating aluminum, and evaporated to dryness while maintaining the temperature at 60 ° C., whereby a uniform film was obtained. Further, aluminum was evaporated to obtain a waveguide type nonlinear optical element. The temperature of the device was raised to 80 ° C., and the device was cooled to room temperature while applying an electric field of 500 V / cm to the upper and lower aluminum electrodes.

This Nd-YAG laser (wavelength 1.064μ)
m) is condensed and irradiated, and the second harmonic of the light (wavelength 0.
532 μm) was observed by a photomultiplier.

Example 4 To 7 parts by weight of the same copolymerized nylon as in Example 1, 3 parts by weight of a butyral resin (BL-1 manufactured by Sekisui Chemical Co., Ltd.) and 2.5 parts by weight of p-nitroaniline were added to 50 parts by weight of ethyl alcohol. Heat to 65 ° C with stirring to dissolve.

Cast the above homogeneous mixed solution on a glass substrate,
The solvent was removed by heating to obtain a uniform host / guest type solid solution on a film having a thickness of about 300 μm.

The solid solution on the film was mechanically strong and flexible, and no special attention was required for handling.

Next, when this host-guest solid solution was irradiated with an Nd-YAG laser (wavelength: 1.064 μm), SHG having about 10 times the intensity of urea by the powder method was observed by a photomultiplier.

Example 5 Nylon terpolymer of 6/66/610 (manufactured by Toray Industries, Inc., CM
4000) 10 parts by weight of 50 parts by weight of ethyl alcohol and p
-Add 2.5 parts by weight of nitroaniline, and stir at 65 ° C
Warm up and dissolve.

Cast the above homogeneous mixed solution on a glass substrate,
The solvent was removed by heating to obtain a uniform host / guest type solid solution on a film having a thickness of about 300 μm.

This film-like solid solution was mechanically strong and had flexibility, and no special attention was required for handling.

Next, when this host guest solid solution was irradiated with an Nd-YAG laser (wavelength: 1.064 μm), SHG having about 16 times the intensity of urea by the powder method was observed by a photomultiplier.

[Effects of the Invention] As described above, according to the present invention, a large amount of a guest organic compound having both an electron-withdrawing group and an electron-donating group is uniformly dissolved in a host polymer compound composed of copolymerized nylon. A host / guest type solid solution can be provided, and the solid solution has excellent mechanical strength and workability, and is suitable for device fabrication.

In addition, even a guest organic compound that has large nonlinearity but easily forms a centrally symmetric crystal by itself and does not have SHG activity, uniform and large SHG activity can be achieved simply by blending with a host polymer compound to form a solid solution. Can be expressed.

Claims (4)

(57) [Claims] 1. A host polymer compound comprising a copolymerized nylon, comprising a guest organic compound having both an electron-withdrawing group and an electron-donating group, wherein the content of the guest organic compound is 100 parts by weight of the host polymer compound. 15 to 90 parts by weight of the solid solution. 2. The solid solution according to claim 1, wherein the guest organic compound is a compound having a centrally symmetric crystal which does not exhibit SHG characteristics by itself. 3. The solid solution according to claim 1, wherein the host polymer compound is blended with a homopolymer of a copolymerized nylon or a polymer compatible with the copolymerized nylon. 4. The solid solution according to claim 1, wherein the copolymer nylon is a terpolymer nylon or a quaternary nylon.